machinery feature | pVc compounding
baseline production size, an 80 mm production machine for custom and toll compounders, and 100 and 150 mm machines for high-capacity production. compounding with the Tri-Kneader has helped some
compounders to save material costs. Because of the high temperatures in TSE compounding, a portion of additives such as curing agents, blowing agents, and others that are activated at high temperatures can be lost during processing. in contrast, the Tri-Kneader maintains a lower temperature, so that these additives are not consumed. lazorchak notes that this has allowed customers to reduce additive levels and obtain substantial cost savings. Another way pVc compounders can save materials
B&P’s TriVolu- tion 60 prototype along with its chief designer Gonzalo Marulanda
compounding rigid pVc, which has a tighter processing window than flexible pVc or other thermoplastics. “The TriVolution opens up the processing window and ensures much better control during compounding to reduce the risk of burning the product. we are generally able to compound at 10o
c lower with the TriVolution than with
standard legacy kneader technology,” he explains. The TriVolution was designed not only to improve
pVc compounding, but to broaden the product range that can be run on a Kneader. it has also been used successfully with starch-based compounds, highly-filled formulations, masterbatches, Tpos and TpEs and more, comments lazorchak. B&p now offers the TriVolution in several sizes: a 30 mm r&d lab table-top (see compounding world’s December article on lab extruders), a 45 mm r&d and pilot line, a 60 mm
costs, in any compounding equipment, is to use gravimetric dosing to starve-feed the machine rather than using the traditional powdered pre-mix fed volumetrically. “gravimetric dosing of individual raw materials eliminates variations presented when you pre- mix the pVc and additives and allows you to improve repeatability of the process,” says lazorchak. He adds, “pre-mixing is a batch process. direct feeding lets you run a completely continuous process, which can increase capacity of the plant and lower the overall process footprint.” in some cases a formulation may have too many components to feed each individually, but compounders may be able to combine methods and use a pre-mix of some components while adding others at the extruder. while not everyone sees a need to break away from traditional pre-mix methods, lazorchak notes that some customers have found using the starve-feed method for pVc compounding is more cost-effective.
Extended capabilities The Buss four-flight Quantec pVc Kneader is designed for both rigid and flexible pVc compounding. An advantage of the Kneader is that most rigid pVc compounds run at the same throughput as flexible pVc, without the 25-30% throughput drop seen with co rotating twin-screws, says mike irish, vice president of Buss Kneader Technology at the Swiss company’s uS subsidiary. The Quantec is now available in a 15 l/d configura-
tion as well as the original 10 l/d. The 15 l/d version is more versatile and allows processing of rigid and flexible pVc compounds, in addition to highly filled pVc compounds, pVc blends, alloys and wood flour filled grades, notes irish. The longer l/d is also optimal for unfilled grades
FiGure 1: CoMParison oF a riGiD PVC ForMulaTion on The TriVoluTion, a Tse, anD B&P’s leGaCy Co-KneaDers in The B&P ProCessinG laB
44 compounding world | January 2012
going into medical tubing, which require very low gel counts. “Because these grades are minimally stabilized, you must control the shear and process at low tempera- tures to avoid overworking and forming gels. At the same time, some grades use high molecular weight
www.compoundingworld.com
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44 |
Page 45 |
Page 46 |
Page 47 |
Page 48 |
Page 49 |
Page 50 |
Page 51 |
Page 52 |
Page 53 |
Page 54 |
Page 55 |
Page 56 |
Page 57 |
Page 58 |
Page 59 |
Page 60 |
Page 61 |
Page 62 |
Page 63 |
Page 64 |
Page 65 |
Page 66 |
Page 67 |
Page 68
